1. Field of the Invention
The invention relates to a buttonhole sewing machine, comprising a needle which is drivable in up and down reciprocation; an x-y table, which is displaceable by an x drive in an x direction and by a y drive in a y direction, and which supports at least a work piece clamp; and a buttonhole sewing device, which is substantially disposed downstream of the needle in the y direction, which comprises a cutter with a knife, which comprises a cutting block unit of several cutting blocks, one of which at a time being movable into a position of cooperation with the knife, and which is provided with a cutting drive.
2. Background Art
A buttonhole sewing machine of the generic type is known from U.S. Pat. No. 6,220,192 B1. In this case, a knife is stationarily, but replaceably mounted on the base plate of the sewing machine. Several cutting blocks are mounted above the knife on a rotary support that is drivable in up and down reciprocation; the cutting blocks can be moved around an axis that extends in the y direction selectively into a position in which a cutting block cooperates with the knife. Pivoting the cutting blocks and setting the support in a given position of a cutting block needs extensive constructional requirements.
It is an object of the invention to embody a buttonhole sewing machine of the generic type such that the constructional requirements for the cutting device are as little as possible.
According to the invention, this object is attained by features wherein an anvil which supports at least two cutting blocks that are adjustable in the x direction is stationarily joined to the sewing machine; and wherein the knife is movable from above against the anvil. By a linear motion which can be extremely short, only extending over the width of a cutting block, the cutting blocks can selectively be moved into a position in which they engage with the knife which is only movable in a straight line. The anvil is mounted on the base plate, having only a single support that is movable only in a single direction, namely the x direction, whereas the knife only makes a vertical linear motion.